Selecting system



1942. c. v. PARKER 2,291,752

SELECTING SYSTEM Fild Feb. 5, 1941 2 Sheets-Sheet l I II-II INVENTOR C. L PARKER "mm W 'ATT RNEV Aug. 4, 1942. c. v. PARKER 2,291,752

SELECTING SYSTEM Filed Feb. 5, 1941 2 Sheets-Sheet 2 A TORN Patented Aug. 4, 1942 SELECTING SYSTEM Carlyle V. Parker, Sunnyside, N. Y., assignor to Bell Telephone Laboratories,

Incorporated,

New York, N. Y., a corporation of New York Application February 5, 1941, Serial No. 377,443

Claims.

This invention relates to selecting and switching systems.

The objects are to improve the usefulness of automatic switching mechanisms by providing for the simultaneous establishment of a plurality of connections; to prevent interference between the separate connections that are being established simultaneously; to prevent double or other false connections; and to increase the flexibility and efficiency, and in other respects to improve selecting and switching systems and mechanisms.

Numerous types of coordinate switching systems have been devised heretofore to! connecting incoming lines to outgoing lines, In these prior systems it is usually necessary to provide some means for serving one incoming line at a time, so that double connections will not result if a number of incoming lines are seeking attention simultaneously.

In accordance with the present invention advantages are realized over these prior switching systems by the provision of means for enabling a plurality of simultaneously calling incoming lines to be connected at the same time to a corresponding number of idle outgoing lines without interference or double connections. More specifically these advantages and also the foregoing objects are realized in a switching system comprising a plurality of discharge tubes arranged coordinately in horizontal and vertical rows, each horizontal row of tubes representing an incoming line and each vertical row of tubes representing an outgoing line. Any incoming line is connectable to any outgoing line by the operation of the. discharge tube at the coordinate cross-point of the incoming and outgoing lines, the connected incoming lin being guarded against subsequent connection to a second-outgoing line by potential changes on the electrodes of all other tubes in the same horizontal row, and, similarly, the connected outgoing line being guarded against subsequent seizure by a second incoming line by potential changes on the electrodes of all tubes in the corresponding vertical row. The tubes are operated by potential impulses of difierent phases, the impulses of a particular phase being applied simultaneously to all tubes in a particular diagonal row, the impulses of the next phase being applied simultaneously to the tubes in th next diagonal row, etc.,- for the other phases. With this arrangement only one tube may be operated at a given instant in any horizontal or vertical row, but all tubes subiect to an impulse of a given phase may be onerated simultaneously provided the associated incoming line is in a calling condition and the associated outgoing line is in a selectable condition. The advantage of this method of operating only those tubes which lie in the same diagonal row in the switching mechanism is that a plurality of connections may be established simultaneously through the switching mechanism without any danger of' interference and without obtaining any false connections.

The foregoing and other features and advantages of this invention will be described more fully in the following detailed specification.

In the drawings accompanying the specification:

Figs. 1 and 2 taken together illustrate a coordinate switching mechanism incorporating the features of this invention;

Fig. 1 shows a plurality of horizontal and ver-' tical rows of discharge tubes for establishing connections between incoming and outgoing lines;

Fig, 2 shows an impulse generating mechanism for producing the operating impulses for the discharge tubes; and

Fig. 3 illustrates an alternative form of the switching, mechanism.

Th switching mechanism disclosed herein may be used for a wide variety of purposes. It may serve to establish connections in telephone, telegraph or other communication systems between subscribers lines or between said lines and links, trunks or other connecting circuits;-it may serve to establish connections between incoming trunks and outgoing trunks; or it may be used for connecting lines, links, trunks or other circuits to switch controlling or marker mechanisms, such as those used in automatic telephone systems. And, as above suggested, it may be used for numerous other purposes.

Referring particularly to the drawings, the switching mechanism disclosed herein serves to establish connections between a number of incoming lines IOI, I02, I03, I04 and a number of outgoing lines I05, I06, I01, I08. While only four incoming lines and four outgoing lines are illustrated, it will be obvious that this number may be increased and that the capacity of the switching mechanism will depend upon the specific use to which it is put.

Each incoming line is represented in the switch by a horizontal row of space-discharge tubes and associated connecting relays. Similarly, each outgoing line is represented in the switch by a vertical row of tubes and relays. For example, lines IOI, I02, I03, I04 are represented respectively by the horizontal rows of tubes III, H2, H3, H4; and the outgoing lines I08, I08, I01, I08 are represented respectively by the vertical rows of tubes iii, H8, H1, H8. The anode of each tube is connected to the winding of a connecting relay associated therewith, and the windings of all connecting relays are connected to the positive pole of battery I82. For example, the anodes I2I, I22, I23, I24 01' tubes I25, I28, I21, I28 are connected respectively to the relays I29, I30, I3I, I32, and these relays are connected over the common conductor I33 to the positive pole of battery I82. The cathodes of all tubes in each vertical row are connected over a common conductor and through a common resistance to the negative pole of battery,

For example, cathodes I34, I35, I38, I 31 of tubes I25, I38, I39, I40 are connected over the common conductor HI and the common resistance I42 to the negative pole of battery I43. The screen or controlling grid elements of the tubes in each horizontal row are connected together and to the positive pole of battery. In the horizontal row III the control grids I44, I45, I48, I41 are connected over conductor I48 through the contacts of a control relay I83 and resistance I84 to the positive pole of battery I85; and the control grids of the tubes in the remaining horizontal rows II2, I I3, II4 are similarly connected. The starting electrodes of the tubes. which cooperate with the cathodes to form the ionizing gaps, are connected to the: impulse conductors 204 from the phase impulse generator 205.

These connections are so chosen that all of the tubes in a diagonal row are connected in multiple to the same impulse conductor. -In the switch mechanism illustrated there are seven diagonal rows of tubes.

tubes I38 and I28; the third, row contains tubes I39, I48 and I21; the fourth row contains tubes I40, I50, I5I and I28; thefifth row contains tubes I52, I53 and I54; the sixth row contains tubes I55 and I58; and the seventh row contains the single tube I51. The starting electrode I58 of the tube I25 in the first diagonal row is connected through resistor I 59, to the No. 1 phase impulse conductor 208; the starting electrodes I80 and I8I of tubes I38 and I28 are connected through resistors to the No. 2

The first row contains the single tube I25; the second row contains 2,285,815 of June 9, 1942, and No. 2,252,766 of August 19, 1941.

phase impulse conductor 201; the starting electrodes I82, I83, and I84 of the three tubes in the third diagonal row are connected through individual resistors to the No. 3- phase impulse conductor 208: and in like manner the starting electrodes of the tubes in the fourth, fifth, sixth the preceding impulse. While the invention is not limited to the use of any particular type of impulse generator, reference may be had, for an understanding of the manner in which these impulses may be generated, to the application of W. H. T. Holden, Serial No. 361,536, filed October 1'7, 1940, and the patents to Holden No.

The discharge tubes used in the switching mechanism illustrated herein may be of any wellknown type. They may have hot or cold cathodes, screen or other control electrodes or separate starting electrodes and gaps; they may be filled with gases such as argon and neon.

A description will now be given of the detailed operation of the selecting system. Assume first that a calling condition appears on some one of the incoming lines, such as line IOI, and that no calling condition appears on any of the other incoming lines at this time. Assume also that all of the outgoing lines I05, I08, I01 and I08 are idle. The calling condition on line IOI causes the operation of relay I83 in any wellknown manner, and the relay I83 connects the positive pole of battery I85 through the resistor I 84 to conductor I48. Thus \the control grids I44, I45, I48 and I41 of the row of tubes III, in which the calling line IOI appears, are raised to the positive potential of the battery I85. Assume that at this particular instant the generator 205 has just completed the delivery of an impulse of phase No. 1 and is about to deliver the next phase impulse over conductor 201. When this next impulse, phase No. 2, appears on the conductor 201, it is applied simultaneously through resistors I85 and I88 to the starting electrodes I80 and I8I respectively of tubes I38 and I28. The starting gaps of both tubes ionize in response to this impulse. The circuit for ionizing the gap I35I80 may be traced from the negative pole of battery I43, resistor I42, conductor I4I, cathode I35, starting electrode I80, resistor I85 to conductor 201 on which the positive potential impulse is present. The circuit for ionizing the gap I81I8I of tube I28 may be traced from the negative pole of battery I88, resistor I89, conductor I10, cathode I81, starting electrode I8I, resistor I88 to the impulse conductor 201 on which the negative impulse is present. Although the control gap of the tube I38 ionizes, ionization does not transfer to the main anode of the tube since no potential exists on the control grid I1I. On the other hand the control grid I45 of tube I28 in the row serving the calling line IOI is at the potential of battery I 85, and the ionization produced in the control gap transfers to the main anode I22. Current now fiows in a circuit traceable from the positive pole of battery I82, conductor I33, winding of relay I30, anode I22, cathode I81, conductor I 10, resistor I89 to the negative pole of battery I88. As soon as ionization transfers to the main anode, current flows from battery I85 through the resistor I84, conductor I 48, grid I45, cathode I81, thence through resistor I89 to the negative pole of battery I88. The fiow of current through the resistor I 84 lowers the positive potential applied to the control grids of all other tubes in the row III, so that ionization cannot transfer from the starting gap to the main anode. Thus the operation of one tube in the horizontal row III disables all of the other tubes in the same row. Similarly the,

gap of any one of these tubes is prevented. Thus '7 the operation of any tube in the vertical row I I8 disables all remaining tubes in the same row. The flow of current in the main anode circuit of the operated tube I26 causes the operation of relay I30, which establishes a connection between the conductors of the calling incoming line IOI and the selected idle outgoing line I06. As long as this connection continues the line IOI is guarded against a double connection with another outgoing line by means of the altered potential on the control grids of all tubes in the horizontal row II I. Also the selected outgoing line I06 is guarded against selection by another incoming line by means of the altered potential on the cathodes of all tubes in the vertical row H6.

the remaining calling lines will then be served.

- To explain this operation assume that lines MI,

Assume next that a plurality of incoming lines,

such as lines IOI, I02 and I04, are calling simultaneously and that an equal number of the outgoing lines are idle at the time, such as lines, I05, I 01 and I08.

When lines IOI, I02 and I04 call, the asso-- ciated relays I83, I86 and I81 operate. Relay I83 applies positive potential from battery I85 through resistor I84 to the control grid of the tubes in the horizontal row III; relay I86 applies positive potential through resistor I88 to the control grids of the tubes in the horizontal row H2; and relay I81 applies positive potential through resistor I89 to the control grids of the tubes in the row II4. Assume also that the generator 205 at this moment is about to deliver a potential impulse of phase No. 4 over impulse conductor 209. When this impulse appears on conductor 209, it is applied through resistors I15, I16, I 11 and I18 to. the starting electrodes of the respective tubes I40, I50, I5I and I28 comprising a diagonal row. The starting gaps of these tubes ionize in response to this potential impulse, and ionization transfers to the main anodes of tubes I40, I5I and I28 since the control grids of these tubes are at positive potential. No transfer takes place, however, in the tube I50.

Anode current now flows in the discharge circuits of tubes I40, I5I and I28, and the associated relays I18, I19 and I32 operate. Relay I18 connects the calling incoming line I04 to the idle outgoing line I05; relay I19 connects incoming line I02 to outgoing line I01; and relay I32 connects incoming line IOI to the outgoing line I08. The flow of grid current through the common resistors I84, I88 and I89 alters the potential on the grids of the tubes in the corresponding rows to prevent the discharge of another tube in any one of these rows, thereby protecting the lines IOI, I02 and I04 from subsequent connection to another outgoing line. Similarly the flow of discharge current through the common resistors I42, I80 and I8I alters the potential on the cathodes of all the tubes in the vertical rows II 5, H1, and H8 to prevent another incoming line from being connected to either of the selected outgoing lines I05, I01 and I08.

Thus the application of a phase impulse of ,a single phase to the corresponding diagonal row of discharge tubes may result in the simultaneous connection of the entire group of calling incoming lines to corresponding outgoing lines. If, however, all of the calling incoming lines are not represented in the diagonal row to which an impulse is being applied at the instant the calls appear, as many of the calling lines will be served as there are idle outgoing lines represented in said diagonal row. Presently, however, impulses of the following phases will be applied in succession to the succeeding diagonal rows, and

I02 and I03 call simultaneously and that the next phase impulse is applied to the diagonal row containing the single tube I25. If the outgoing line I05 is idle at this moment, tube I25 discharges/and the calling line MI is connected to line I05. An instant later the next phase impulse is applied to tubes I38 and I26. Both of these tubes, however, are disabled by the operation of tube I25, and neither of them discharges. An instant later an impulse is applied to tubes I39, I48 and I 21. In this diagonal row tubes I39 and I21 have been disabled by the operated tube I25, but tube I49 now discharges, provided the outgoing line I06 is idle, and the second calling line I02 is thereby connected to the line I08. Subsequently a phase impulse is applied to the diagonal row containing tubes I52, I53 and,

I54, and tube I53 operates, provided the circuit I01 is already idle, and the third calling line I03 is connected to the outgoing line I 01.

The connections established from the calling lines to the called lines may be held in any suitable and well-known manner by maintaining the connecting relays in an energized condition. If desirable, theline relays I83, I86, etc., may be disconnected in the usual manner by means of cutoff relays.

If desirable the switching tubes disclosed in Fig. 1 may be replaced by tubes having separate control gaps. A single row 300 of switching tubes of this type is illustrated in Fig. 3. For example, the tube 30I is provided with a main anode 302, a main cathode 303 and an ionizing gap comprising a starting anode'304 and a starting cathode 305. When an impulse of phase No. 1 is applied to the starting anode 304, the starting gap ionizes, and ionization transfers to the main anode 302. Current now flows from the positive pole of battery 306 through the contacts of the operated relay 301, inductor 308, anode 302, cathode 305, resistor 309, to the negative pole of battery 3I0. The voltage drop in the resistor 300 alters the potential on the starting cathodes of all other tubes in the same vertical row to prevent a second tube from ionizing. Shortly after the initial transfer of ionization a transfer takes place between the main anode and main cathode of the tube, and current now flows from the main anode 302 to the cathode 303 thence through the work relay ill I to the negative pole of battery. When discharge current is rising in the circuit above traced, the inductor 308 produces a voltage drop which is applied to the anodes of all tubes in the horizontal row 300 to render them inefiective. As soon as the current in the discharge circuits reaches its steady state, the drop due to the resistance of the element 308 lowers the positive potential on the anodes in the row 300 to prevent a second tube from operating,

During the time a connection is maintained, discharge current flows from the main anode to the main cathode and also to the starting cathode. This continued fiow of current through the common resistor 309 in the circuit of the starting cathodes lowers the negative potential of all starting cathodes in the corresponding vertical row of tubes to prevent a second one of these tubes from ionizing when phase impulses are applied to the starting anodes.

What is claimed is:

1. The combination in a selecting system of a plurality of incoming circuits, a plurality of outgoing circuits, each incoming circuit being con- -means for producing impulses of a plurality of nectable to each outgoing circuit, a plurality of discharge devices arranged in coordinate series, the several series of devices in one coordinate direction serving respectively the several incoming circuits, the several series of devices in the other coordinate direction serving respectively the several outgoing circuits, means for producing impulses, and circuit means-iciapplying said impulses simultaneously to a group of said devices comprising one. device in each of a plurality of series in both coordinate directions, the devices of said group which correspond to calling incoming circuits and to selectable outgoing circuits operating simultaneously in response to said impulses to eirect connections between the calling incoming circuits and the respective selectable outgoing circuits.

2. The combination in a selecting system of a plurality of incoming circuits, a plurality of outgoing'circuts, said incoming circuits being connectable to said outgoing circuits, a plurality of discharge devices arranged in coordinate rows, the several rows or devices in one coordinate direction serving respectively the several incoming circuits, the several rows oidevices in the other coordinate direction serving respectively the several outgoing circuits, means for producing impulses of a plurality of phases, means for applying impulses of the successive phases respectively to successive groups of said devices, each group oi devices, comprising one device in each 01' a plurality of rows in one coordinate direction and one device in each oi a plurality of rows in the other coordinate direction, the devices of each group which correspond tocalling incoming circuits and to selectable outgoing circuits operating simultaneously in response to the impulses applied thereto to eflect connections between the incoming circuits and the outgoing circuits.

3. The combination in a switching system of a plurality oi! incoming circuits, a plurality of outgoing circuits, said incoming circuits being condiii'erent phases, circuit means for applying the impulses or the successive phases respectively to successive groups of tubes, each group of tubes comprising a tube in each of a plurality of rows in both coordinate directions, the tubes oi any one of said groups which correspond to calling incoming circuits and selectable outgoing circuits operating in response to said impulses, means responsive to the operated tubes for connecting the incoming circuits to the outgoing circuits, and means eflective in response to the operation of one of said tubes for rendering ineiiective the remaining tubes in the coordinate rows containing the operated tube.

4. The combination in a switching system of incoming lines and outgoing lines, said incoming lines being connectable to said outgoing lines, a plurality of discharge tubes arranged in horizon tal and vertical rows, the tubes 01' said horizontal and vertical rows forming diagonal rows, the horizontal rows serving the respective incoming lines and the vertical rows serving the respective outgoing lines, means for producing impulses, cir-' cuit means for applying said impulses simultaneously to the tubes oi! a diagonal row, the tubes oi! said diagonalrow which correspond to calling incoming lines and idle outgoing lines operating simultaneously in response to said impulses, and means responsive to the operated tubes for connecting the incoming lines to the outgoing 1 es.

5. The combination in a switching system oi incoming lines and outgoing lines, said incoming lines. being connectable to said outgoing lines, a plurality oi discharge tubes arranged in coordinate rows, the tubes of saldcoordinate rows forming diagonal rows, the tubes 01 the rows in one coordinate direction serving the respective in coming lines and the tubes of the rows in the other coordinate direction serving the respective outgoing lines, means for producing impulses of a series of diflerent phases and for repeating said impulses cyclically, the impulses oi the successive phases corresponding respectively to the successive diagonal rows of discharge tubes, circuit means for applying the impulses of each phase simultaneously to the tubes or the corresponding diagonal row, the tubes of any diagonal row which at the time the impulses are applied thereto correspond to incoming lines that are in a calling condition and to outgoing lines that are in an idle condition operating simultaneously in response to said impulses, and means responsive to the operated tubes for connecting the in coming lines to the outgoing lines.

CARLYLE V. PARKER. 

